Thermionic vapor tube



Dec. 5, 1933. c. J. BIVER THERMIONIC VAPOR TUBE Filed Feb. 24. 1952 Carl John B62262- dam 3 Patented Dec. 5,1933

1,938,211 THERMIONIC VAPOR TUBE.

Carl, John Biver, Owensboro, Ky., assignor to I The Ken-Rad Corporation, Owensboro, Ky, a corporation of Kentucky Application February 24,1932. Serial No. 594,939

3 Claims.

It is an object of my invention to providea thermionic tube of the vapor type having an improved construction in itscontrol grid.

- Fig. 1 is a perspective showing of athermionic tube embodying my invention. I

Fig. 2 is a diagrammatic showing of the grouping of the active elements in the tube of my invention, with parts in section, and with parts omitted to avoid confusion'of lines.

In the drawing:

The numeral 10 indicates generally a thermionic tube of the mercury vapor type in which mercury is vaporized to afford a conducting medium. Such tubes usually contain a cathode electron emitter, a control grid and an anode, all suitably supported on the glass stem of the tube, To avoid confusion of lines the supporting wires for the several elements of the tubes have been omitted in Fig. 2. Referring particularly to Fig.

2, a heating element 11' is positioned within a cylindrical cathode 12, and a cylindrical anode 13 is placed about the cathode 12, in spaced relation thereto. A cylindrical screen 14 of woven wire is placed about the anode 13, in spaced relation thereto, and extending above and below the upper and lower edges of the anode. A suitable. disc 15, having a central aperture 16, substantially closes the upper end of the screen 14. The aperture 16 is provided to permit supporting wires or conductors for the heatingfilament and the cathode to extend therethrough and when the filament and cathode are so connected or supported that wires do not extend above the disc then the disc is made solid, to prevent the passage of ions and electrons therethrough. When the disc' 15 isfaperturedthis aperture is substantially closed by a mica disc 17 through which the. upwardly extending wires are passed.

A cylindrical screen grid 18 is interposed between the cathode 12 and the anode 13, and this grid 18 is connected to the screen 14 to'torm a control element indicated generally by the numerals 19. 7

It will now be obvious that the potential of the. control element 19 appears in the space between "the cathode and the anode, and also-in the space between the anode and the glass wall of the tube. I am aware that many changes may be made and numerous details of construction may be varied through a wide range without departing from the principles of this invention, and I therefore do not purpose limiting the patent granted thereon otherwise than necessitated by the prior art.

I claim:

l. A vapor type tube comprising a cathode anda cylindrical anode and being provided with a vaporizable conducting medium, a control grid for the tube comprising a pair of connected equipotential members, one of which is positioned between said cathode and said anode and the other between said anode, and the wall of the tube,

said other member being arranged extending above andbelow said anode.

2.'In a mercury vapor tube, a vertically posi tioned tubular conductive shield provided with means substantially closing the upper end of said shield against the passage of ions through 1 that end, an anode within said shield, a cathode within said shield, and agrid within said'shield between said cathode and said anode conductively connected to said shield.

"3. A mercuryvapor tube comprising a cylindrical cathode, a coiled control grid spacedly surrounding said cathode, a cylindrical anode spacedly positioned about said coiled grid, a cylindrical woven mesh grid spacedly surrounding said anode and extending above and below said anode, ametallic disc conductively connecting the upper ends of said grids defining a tubular conductive shield therewith, and means including said disc substantially closing the upper end of said shield against the passage of ions'through that end. 

